package com.mall.seckill.service.impl;

import com.alibaba.csp.sentinel.Entry;
import com.alibaba.csp.sentinel.SphU;
import com.alibaba.csp.sentinel.annotation.SentinelResource;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.TypeReference;
import com.baomidou.mybatisplus.core.toolkit.IdWorker;
import com.mall.common.to.mq.SeckillOrderTo;
import com.mall.common.utils.R;
import com.mall.common.vo.MemberResVo;
import com.mall.seckill.feign.CouponFeignService;
import com.mall.seckill.feign.ProductFeignService;
import com.mall.seckill.interceptor.LoginUserInterceptor;
import com.mall.seckill.service.SeckillService;
import com.mall.seckill.to.SeckillSkuRedisTo;
import com.mall.seckill.vo.SeckillSessionsWithSkus;
import com.mall.seckill.vo.SkuInfoVo;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RSemaphore;
import org.redisson.api.RedissonClient;
import org.springframework.amqp.rabbit.core.RabbitTemplate;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.BoundHashOperations;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;
import org.springframework.util.StringUtils;

import java.util.*;
import java.util.concurrent.TimeUnit;
import java.util.regex.Pattern;
import java.util.stream.Collectors;

@Slf4j
@Service
public class SeckillServiceImpl implements SeckillService {

    @Autowired
    CouponFeignService couponFeignService;

    @Autowired
    ProductFeignService productFeignService;

    @Autowired
    StringRedisTemplate redisTemplate;

    @Autowired
    RabbitTemplate rabbitTemplate;

    @Autowired
    RedissonClient redissonClient;

    private final String SESSION_CACHE_PREFIX = "seckill:sessions:";
    private final String SKUKILL_CACHE_PREFIX = "seckill:skus";

    private final String SKU_STOCK_SEMAPHORE = "seckill:stock:"; // + 商品随机码

    @Override
    public void uploadSeckillSkuLatest3Days() {
        // 1、扫描最近三天需要参与秒杀的活动
        R session = couponFeignService.getLates3DaySession();
        if (session.getCode() == 0) {
            // 上架商品
            List<SeckillSessionsWithSkus> sessionData = session.getData(new TypeReference<List<SeckillSessionsWithSkus>>() {
            });
            // 缓存到redis
            if (sessionData != null) {
                // 1、缓存活动信息
                saveSessionInfos(sessionData);
                // 2、缓存活动的关联商品信息
                saveSessionSkuInfos(sessionData);
            }
        }
    }

    public List<SeckillSkuRedisTo> blockHandler(BlockException e){
        log.error("getCurrentSeckillSkusResoure...被限流了");
        return null;
    }

    /**
     * blockHandler  函数会在原方法被限流/降级/系统保护的时候调用，而 fallback 函数会针对所有类型的异常。
     * @return
     */
    // 返回当前时间可以参与的秒杀商品信息
    @SentinelResource(value = "getCurrentSeckillSkusResoure",blockHandler = "blockHandler")
    @Override
    public List<SeckillSkuRedisTo> getCurrentSeckillSkus() {
        // 1、确定当前时间属于哪个秒杀场次。
        long time = new Date().getTime();

        try (Entry entry = SphU.entry("seckillSkus")) {

            Set<String> keys = redisTemplate.keys(SESSION_CACHE_PREFIX + "*");
            for (String key : keys) {
                String replace = key.replace(SESSION_CACHE_PREFIX, "");
                String[] s = replace.split("_");
                long start = Long.parseLong(s[0]);
                long end = Long.parseLong(s[1]);
                if (time >= start && time <= end) {
                    // 2、获取这个秒杀场次需要的所有商品信息
                    List<String> range = redisTemplate.opsForList().range(key, -100, 100);
                    BoundHashOperations<String, String, String> hashOps = redisTemplate.boundHashOps(SKUKILL_CACHE_PREFIX);
                    List<String> list = hashOps.multiGet(range);
                    if (list != null) {
                        List<SeckillSkuRedisTo> collect = list.stream().map(item -> {
                            SeckillSkuRedisTo redis = JSON.parseObject((String) item, SeckillSkuRedisTo.class);
//                        redis.setRandomCode(null); // 当前秒杀开始就需要随机码
                            return redis;
                        }).collect(Collectors.toList());
                        return collect;
                    }
                    break;
                }
            }
        } catch (BlockException e) {
            log.error("资源被限流", e.getMessage());
        }
        return null;
    }

    @Override
    public SeckillSkuRedisTo getSkukillInfo(Long skuId) {

        // 1、找到所有需要参与秒杀的商品dekey
        BoundHashOperations<String, String, String> hashOps = redisTemplate.boundHashOps(SKUKILL_CACHE_PREFIX);
        Set<String> keys = hashOps.keys();
        if (keys != null && keys.size() > 0) {
            String regx = "\\d+-" + skuId;
            for (String key : keys) {
                if (Pattern.matches(regx, key)) {
                    String json = hashOps.get(key);
                    SeckillSkuRedisTo redisTo = JSON.parseObject(json, SeckillSkuRedisTo.class);
                    // 随机码
                    long current = new Date().getTime();
                    if (current >= redisTo.getStartTime() && current <= redisTo.getEndTime()) {

                    } else {
                        redisTo.setRandomCode(null);
                    }
                    return redisTo;
                }
            }
        }

        return null;
    }

    // TODO 上架秒杀商品的时候，每一个数据都有过期时间
    // TODO 秒杀后续的流程，简化了收货地址等信息
    @Override
    public String kill(String killId, String key, Integer num) {

        long s1 = System.currentTimeMillis();
        MemberResVo resVo = LoginUserInterceptor.loginUser.get();

        // 1、获取当前秒杀商品的详细信息
        BoundHashOperations<String, String, String> hashOps = redisTemplate.boundHashOps(SKUKILL_CACHE_PREFIX);

        String json = hashOps.get(killId);
        if (StringUtils.isEmpty(json)) {
            return null;
        } else {
            SeckillSkuRedisTo redisTo = JSON.parseObject(json, SeckillSkuRedisTo.class);
            // 校验合法性
            Long startTime = redisTo.getStartTime();
            Long endTime = redisTo.getEndTime();
            long time = new Date().getTime();
            long ttl = endTime - time;
            // 1、校验时间的合法性
            if (time >= startTime && time <= endTime) {
                // 2、校验随机码和商品id
                String randomCode = redisTo.getRandomCode();
                String skuId = redisTo.getPromotionSessionId() + "-" + redisTo.getSkuId();
                if (randomCode.equals(key) && killId.equals(skuId)) {
                    // 3、验证购物数量是否合理
                    if (num <= redisTo.getSeckillLimit().intValue()) {
                        // 4.验证这个人是否已经购买。幂等性；如果只要秒杀成功，就去占位
                        String redisKey = resVo.getId() + "_" + skuId;
                        // 自动过期
                        Boolean aBoolean = redisTemplate.opsForValue().setIfAbsent(redisKey, num.toString(), ttl, TimeUnit.MILLISECONDS);
                        if (aBoolean) {
                            // 占位成功说明从来没有买过

                            RSemaphore semaphore = redissonClient.getSemaphore(SKU_STOCK_SEMAPHORE + randomCode);
                            boolean b = semaphore.tryAcquire(num);
                            if (b) {
                                // 秒杀成功
                                // 快速下发，发送MQ消息 10ms
                                String timeId = IdWorker.getTimeId();
                                SeckillOrderTo orderTo = new SeckillOrderTo();
                                orderTo.setOrderSn(timeId);
                                orderTo.setMemberId(resVo.getId());
                                orderTo.setNum(num);
                                orderTo.setPromotionSessionId(redisTo.getPromotionSessionId());
                                orderTo.setSkuId(redisTo.getSkuId());
                                orderTo.setSeckillPrice(redisTo.getSeckillPrice());
                                rabbitTemplate.convertAndSend("order-event-exchange", "order.seckill.order", orderTo);
                                long s2 = System.currentTimeMillis();
                                System.out.println("耗时。。。{}" + (s2 - s1));
                                return timeId;
                            }

                        } else {
                            // 说明已经买过
                            return null;
                        }
                    }
                } else {
                    return null;
                }
            } else {
                return null;
            }
        }

        return null;
    }

    private void saveSessionInfos(List<SeckillSessionsWithSkus> sessions) {
        sessions.stream().forEach(session -> {
            Long startTime = session.getStartTime().getTime();
            Long endTime = session.getEndTime().getTime();
            String key = SESSION_CACHE_PREFIX + startTime + "_" + endTime;
            if (!redisTemplate.hasKey(key)) {
                List<String> collect = session.getRelationSkus().stream().map(item -> item.getPromotionSessionId() + "-" + item.getSkuId()).collect(Collectors.toList());
                // 检查 collect 是否为空
                if (collect != null && !collect.isEmpty()) {
                    // 缓存活动信息
                    redisTemplate.opsForList().leftPushAll(key, collect);
                } else {
                    // 处理 collect 为空的情况
//                    System.out.println("collect is empty for session: " + session);
                }
            }

        });
    }

    private void saveSessionSkuInfos(List<SeckillSessionsWithSkus> sessions) {
        sessions.stream().forEach(session -> {
            // 准备hash操作
            BoundHashOperations<String, Object, Object> ops = redisTemplate.boundHashOps(SKUKILL_CACHE_PREFIX);
            session.getRelationSkus().stream().forEach(seckillSkuVo -> {
                // 4、商品的随机码
                String token = UUID.randomUUID().toString().replace("-", "");

                if (!ops.hasKey(seckillSkuVo.getPromotionSessionId() + "-" + seckillSkuVo.getSkuId())) {
                    // 缓存商品
                    SeckillSkuRedisTo redisTo = new SeckillSkuRedisTo();
                    // 1、sku的基本数据
                    R skuInfo = productFeignService.getSkuInfo(seckillSkuVo.getSkuId());
                    if (skuInfo.getCode() == 0) {
                        SkuInfoVo info = skuInfo.getData("skuInfo", new TypeReference<SkuInfoVo>() {
                        });
                        redisTo.setSkuInfo(info);
                    }

                    // 2、sku的秒杀信息
                    BeanUtils.copyProperties(seckillSkuVo, redisTo);

                    // 3、设置上当前商品的秒杀时间信息
                    redisTo.setStartTime(session.getStartTime().getTime());
                    redisTo.setEndTime(session.getEndTime().getTime());

                    redisTo.setRandomCode(token);
                    String s = JSON.toJSONString(redisTo);
                    ops.put(seckillSkuVo.getPromotionSessionId() + "-" + seckillSkuVo.getSkuId(), s);

                    // 如果当前这个场次的商品的库存信息已经上架，就不需要上架
                    //5、使用库存作为分布式的信号量 限流
                    RSemaphore semaphore = redissonClient.getSemaphore(SKU_STOCK_SEMAPHORE + token);
                    // 商品可以秒杀的数量作为信号量
                    semaphore.trySetPermits(seckillSkuVo.getSeckillCount().intValue());
                }
            });
        });
    }

}
